Polycystic kidney

Polycystic kidney disease (PKD) is an inherited disorder in which clusters of cysts develop primarily within your kidneys, causing your kidneys to enlarge and lose function over time. Cysts are noncancerous round sacs containing fluid. The cysts vary in size, and they can grow very large. Having many cysts or large cysts can damage your kidneys.

Polycystic kidney disease also can cause cysts to develop in your liver and elsewhere in your body. The disease can cause serious complications, including high blood pressure and kidney failure.

PKD varies greatly in its severity, and some complications are preventable. Lifestyle changes and treatments might help reduce damage to your kidneys from complications.

When to see a doctor

It's not uncommon for people to have polycystic kidney disease for years without knowing it.

If you develop some of the signs and symptoms of polycystic kidney disease, see your doctor. If you have a first-degree relative — parent, sibling or child — with polycystic kidney disease, see your doctor to discuss screening for this disorder.

Causes

Autosomal dominant inheritance pattern

Autosomal dominant inheritance pattern

In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one mutated gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this case, the father — has a 50 percent chance of having an affected child with one mutated gene (dominant gene) and a 50 percent chance of having an unaffected child with two normal genes (recessive genes).

Autosomal recessive inheritance pattern

Autosomal recessive inheritance pattern

To have an autosomal recessive disorder, you inherit two mutated genes, one from each parent. These disorders are usually passed on by two carriers. Their health is rarely affected, but they have one mutated gene (recessive gene) and one normal gene (dominant gene) for the condition. With each pregnancy, two carriers have a 25 percent chance of having an unaffected child with two normal genes (left), a 50 percent chance of having an unaffected child who is also a carrier (middle), and a 25 percent chance of having an affected child with two recessive genes (right).

Abnormal genes cause polycystic kidney disease, which means that in most cases, the disease runs in families. Rarely, a genetic mutation occurs on its own (spontaneous), so that neither parent has a copy of the mutated gene.

The two main types of polycystic kidney disease, caused by different genetic flaws, are:

Autosomal dominant polycystic kidney disease (ADPKD). Signs and symptoms of ADPKD often develop between the ages of 30 and 40. In the past, this type was called adult polycystic kidney disease, but children can develop the disorder.

Only one parent needs to have the disease for it to pass to the children. If one parent has ADPKD, each child has a 50 percent chance of getting the disease. This form accounts for about 90 percent of cases of polycystic kidney disease.

Autosomal recessive polycystic kidney disease (ARPKD). This type is far less common than is ADPKD. The signs and symptoms often appear shortly after birth. Sometimes, symptoms don't appear until later in childhood or during adolescence.

Both parents must have abnormal genes to pass on this form of the disease. If both parents carry a gene for this disorder, each child has a 25 percent chance of getting the disease.

Complications

Complications associated with polycystic kidney disease include:

High blood pressure. Elevated blood pressure is a common complication of polycystic kidney disease. Untreated, high blood pressure can cause further damage to your kidneys and increase your risk of heart disease and stroke.

Loss of kidney function. Progressive loss of kidney function is one of the most serious complications of polycystic kidney disease. Nearly half of those with the disease have kidney failure by age 60.

PKD can interfere with the ability of your kidneys to keep wastes from building to toxic levels, a condition called uremia. As the disease worsens, end-stage kidney (renal) failure may result, necessitating ongoing kidney dialysis or a transplant to prolong your life.

Pregnancy complications. Pregnancy is successful for most women with polycystic kidney disease. In some cases, however, women may develop a life-threatening disorder called preeclampsia. Those most at risk have high blood pressure before they become pregnant.

Growth of cysts in the liver. The likelihood of developing liver cysts for someone with polycystic kidney disease increases with age. While both men and women develop cysts, women often develop larger cysts. Female hormones might contribute to cyst development.

Development of an aneurysm in the brain. A balloonlike bulge in a blood vessel (aneurysm) in your brain can cause bleeding (hemorrhage) if it ruptures. People with polycystic kidney disease have a higher risk of aneurysm. People with a family history of aneurysm seem to be at highest risk.

Heart valve abnormalities. As many as 1 in 4 adults with polycystic kidney disease develops mitral valve prolapse. When this happens, the valve no longer closes properly, which allows blood to leak backward.

Colon problems. Weaknesses and pouches or sacs in the wall of the colon (diverticulosis) may develop in people with polycystic kidney disease.

Chronic pain. Pain is a common symptom for people with polycystic kidney disease. It often occurs in your side or back. The pain can also be associated with a urinary tract infection, a kidney stone or a malignancy.

Prevention

If you have polycystic kidney disease and you're considering having children, a genetic counselor can help you assess your risk of passing the disease to your offspring.

Keeping your kidneys as healthy as possible may help prevent some of the complications of this disease. One of the most important ways you can protect your kidneys is by managing your blood pressure.

Here are some tips for keeping your blood pressure in check:

Take the blood pressure medications prescribed by your doctor as directed.

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